Questions tagged [superblock]

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Recovering ext4 superblocks

Recently, my external hard drive enclosure failed (the hard drive itself powers up in another enclosure). However, as a result, it appears its EXT4 file system is corrupt. The drive has a single ...
tlvince's user avatar
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8 votes
1 answer
5k views

Difference between backup superblocks

Recently I accidentally formatted an EXT4 partition to FAT. I got into a panic. After a long journey through a dark wood in which my hope was fading I could recover my partition and it seems ok. After ...
Dante's user avatar
  • 83
8 votes
2 answers
11k views

Btrfs super-recover says all superblocks are good but mount disagrees

I have an external drive formatted with BTRFS that seems refuses to mount: $ sudo mount -vs -t btrfs -o ro,recovery,errors=continue /dev/sdb2 /media/user/dir mount: /dev/sdb2: can't read superblock ...
Livius's user avatar
  • 241
7 votes
1 answer
7k views

How can I dump the contents of a filesystem's superblock?

I understand that I can list the location of a filesystem's superblocks using the following commands. Example First get the device handle for the current directory. $ df -h . Filesystem ...
slm's user avatar
  • 370k
5 votes
3 answers
49k views

How to fix if I received mount: /dev/vgname/lvname: can't read superblock for the local filesystem?

I received an incident when I was trying to do mount -a . I was getting the below error. So how to fix this issue? mount: /dev/vgname/lvname: can't read superblock
sagar hedaoo's user avatar
4 votes
3 answers
8k views

lost superblock in md raid

Issue on Red Hat Linux 5. Due to some miscommunication two LUNs in our environment were enlarged from 1.2 TB to 1.7 TB. Now, after a reboot, mdadm does not find the superblocks to build the array ...
ddeimeke's user avatar
  • 4,587
4 votes
3 answers
11k views

Data recovery from an accidental format on ext4 partition

When I was installing Mint Debian edition unlike the classic edition, the installation automatically formated my home partition when I did not specify to format. So the formatting previously was ext4 ...
Neovatar's user avatar
4 votes
2 answers
14k views

Can't load Ubuntu: Superblock checksum does not match superblock while trying to open /dev/sda7

I have a problem while loading into Ubuntu 17.04. This happens for the 2nd time after I booted into Windows. For the 1st time I just reinstalled the Ubuntu. I am not good at this question, so I hope ...
kozlone's user avatar
  • 75
4 votes
1 answer
4k views

mdadm - Accidentally ran "mdadm --create" on an existing raid-1. The superblock is now corrupt and I am unable to recover data. Did I bork my data?

I have /dev/sdb1 and /dev/sdc2 that were previously setup into a RAID-1 with mdadm, but then I reinstalled and lost the old configuration. Out of idiocy, I ran sudo mdadm --create /dev/md0 --level=1 ...
bestephe's user avatar
4 votes
1 answer
3k views

Ext2 block structure: size of reserved GDT Blocks

In every publication I found about ext2, the structure of a block group is defined as following: Super Block: 1 block Group Descriptor: N blocks Data Bitmap: 1 block Inode Bitmap: 1 block Inode Table:...
goose999's user avatar
4 votes
3 answers
17k views

ext4 - Bad magic number in super-block

ext4 is failed me again! the most unstable fs tried to fix it by restoring block from backup, but without luck.. ↪ sudo fsck.ext4 -v /dev/sdd e2fsck 1.45.6 (20-Mar-2020) ext2fs_open2: Bad magic number ...
Yu Da Chi's user avatar
4 votes
1 answer
17k views

e2fsck: unable to set superblock flags on LogicalVolume

When I boot my machine either in normal mode or runlevel 1 it throws following error and I'm unable to boot the machine: checking filesystems /dev/MyGroup/LogVol00: UNEXPECTED INCONSISTENCY; RUN ...
user2914's user avatar
  • 2,651
4 votes
2 answers
2k views

Access ext4 disk that lost superblock and its backups

I found myself in a weird situation with my system's disk. It's Linux system with 3 partitions, boot, swap and filesystem (ext4). A few days ago i used knoppix from a pendrive (I made the bootable usb ...
valepu's user avatar
  • 192
3 votes
1 answer
7k views

How to fix BTRFS superblock error after resize/shrink (BTRFS: couldn't get super buffer head for bytenr 274877906944)

BTRFS RAID1 array with 2 500 GB hdds, no errors. This is the root filesystem, so there are 3 partitions on each drive: 1 = /boot (ext4), 2 = / (btrfs), 3 (swap) /boot is ext4 because upgrading the ...
basic6's user avatar
  • 6,255
3 votes
1 answer
3k views

Fixing missing superblocks on both RAID1 disks using mdadm

My RAID1 array was working fine at /dev/md128 but seems to have completely disappeared after a reboot, with mdadm reporting both disks are missing superblocks. My question is how to fix this? ...
tater's user avatar
  • 273
3 votes
2 answers
5k views

Creating disk device in a file

I'm trying to create disk device in a file with: dd if=/dev/zero of=file.img bs=516096 count=1000 sudo losetup /dev/loop0 file.img (echo n; echo p; echo 1; echo ""; echo ""; echo w;) | sudo fdisk -u -...
0xAX's user avatar
  • 627
3 votes
2 answers
731 views

List what each sd is

On Linux I know that sda, sdb, and sdh are hard drives, but I don't know what is sdc, sdd, sde, sdf and sdg are. Some of them are (I think) empty and some of them, the kernel tries to make them ...
aaa's user avatar
  • 157
3 votes
3 answers
6k views

How can I identify the filesystem/partition type

My hard drive got corrupted at some point after mounting an mtpfs system. I would ask how to fix that, but I'm not confident about the partition and file system types. My OS is new Fedora Core 23, ...
Id Rathernotsay's user avatar
3 votes
1 answer
4k views

All my superblocks are corrupt!

I am having a problem with my ubuntu ext3 filesystem. I can't boot from it or mount the volume when running live CD. When I try e2fsck I get: "Bad magic number in super-block while trying to open /...
thepeer's user avatar
  • 131
3 votes
1 answer
4k views

Internal disk failed with bad superblock, how to fix? [closed]

NOTE: The operating system I'm using is on a separate disk (/dev/sdb). I tried to mount my old root partition (/dev/sda12) as usual with the following command: sudo mount /dev/sda12 /mnt However, ...
InitializeSahib's user avatar
3 votes
1 answer
2k views

Relation between "Block Size"and "Upper Limits" in ext2

A similar looking question asks for the reason why the upper file limit could be 2 TB in ext2. I am trying to understand but the Documentation on ext2 but find this hard. Please correct me if I'm ...
erch's user avatar
  • 5,030
2 votes
1 answer
2k views

Superblock replicas in ext4

I am trying to find the association between block groups and superblocks in an ext4 filesystem I was unable to find much of documentation online, except this link that hints that Because of the ...
pkaramol's user avatar
  • 2,799
2 votes
2 answers
1k views

mdadm metadata: should i take precautions to prevent superblock overwrite?

Situation: I'm creating a new RAID1 array using mdadm. I won't be using additional layers, such as LVM or dm-crypt. I've noticed that metadata version 1.2 is now the default. I understand it's the ...
Martijn's user avatar
  • 129
2 votes
1 answer
1k views

mdadm + lvm2: destroyed all superblocks accidentally

I accidentally overwrote all my RAID1 superblocks with garbage. I think this happened because I ALT-CTRL-DEL booted when the Ubuntu had put me in some kind of hard disk recovery mode. My display wasn'...
exDM69's user avatar
  • 121
2 votes
1 answer
3k views

Unable to mount /home/ partition after reinstalling grub after reinstalling windows 7

I've reinstall windows 7 on it's asignated partition and, as usually, it override the MBR with it's own stuff and, thus, it was not possible to boot to my ubuntu 12.04 partition. I followed the step ...
authchir's user avatar
  • 127
2 votes
1 answer
8k views

How can I view the superblock of an XFS partition?

I know that EXT superblock information can be found using dumpe2fs -h /dev/sda1, but what is the XFS equivalent of this? The best I have found so far is xfs_info /dev/sda1, but this doesn't seem to ...
Timothy Pulliam's user avatar
2 votes
1 answer
3k views

Filesystem: How to find block of file represented by inode? [closed]

I am writing a file system for my operating system and am doing research on existing file systems before I start designing my own. I came across some slides about the System Five File System and am ...
MrPickles's user avatar
  • 133
2 votes
1 answer
3k views

Physical volumes, logical volumes, superblocks gone... how to boot?

A story fairly similar to this one happened to me yesterday. Update: My only hard drive /dev/sda was originally partitioned this way: Device Boot Start End Blocks Id System /dev/...
Pit's user avatar
  • 55
2 votes
2 answers
677 views

Rebuilding directory tree (and/or inodes)

Problem My Armbian based Orange Pi webserver crashed (probably because of a power loss). I thought it would be fine since ext4 is more resilient and it usually has been in the past, but for some ...
Synetech's user avatar
  • 173
2 votes
1 answer
3k views

EXT4 app2sd link2sd partition repair with bad superblock . Partition cannot be mounted on Android but will mount RW w/ su on Linux Live

I have a 128gb micro sd formatted as ext4 10gb for app2sd 2nd ext4 partition ( p2 ) on my Android 6 phone . All my apps ( 80%) stay on that ext4 partition . Now app2sd cant load this partition - "...
user1874594's user avatar
2 votes
0 answers
217 views

Raid can be assembled but not mounted, issue is with the superblock

I moved tow drives which where mounted in a raid1 to another to a new system to be mounted there. One drive was detected instantly, the other one had issues with the super blocks. After reading Kevin ...
Friedi's user avatar
  • 21
2 votes
1 answer
169 views

What is the most efficient way to search a block device for valid (filesystem) superblocks?

I have a block device that contains some valid filesystem (including the main and backup superblocks) at some unknown offset with some unknown block size. In my case I happen to know that it's an ext4 ...
ATLief's user avatar
  • 309
2 votes
0 answers
463 views

Why do my software RAID1 superblocks keep getting corrupted and how can I prevent this?

How might I be repeatedly corrupting my superblocks on RAID1 I have had two occasions in the past six months of RAID1 root arrays becoming unusable because of problems with the superblock. ...
Stonecraft's user avatar
2 votes
1 answer
293 views

How to recover when ext4 superblock's inode count is reset to 0

We tried to resize a 15TB ext4 partition to 16TB and accidentally managed to hit an old (and fixed in newer releases) off-by-one bug of ext4_resize_fs() which causes inode count to reset to 0 thanks ...
Matti K's user avatar
  • 21
2 votes
0 answers
1k views

fsck fails frequently(after each 3-4 boots)

I have triple boot System(Ubuntu,Kali,Win7) and I mostly use Kali linux(4.6.0-kali1-amd64). After each 3 or 4 successful boots i get this error -> fsck.ext4: Superblock checksum does not match ...
Dirty_Programmer's user avatar
2 votes
1 answer
3k views

Short read while trying to open /dev/sda2

I just resized a .vdi from my host from 15.5G to 120G. I tried to resize the partition from the guest (ubuntu server) using resize2fs root@ubuntu:~# sudo resize2fs /dev/sda2 115G resize2fs 1.42.13 (...
l'arbre's user avatar
  • 123
2 votes
0 answers
3k views

Superblock corruption on every boot

I have a Linux Mint 12 install on my laptop. Yesterday I powered it off like I always do and this morning when I started it I was greeted by an error screen. (Translated from Swedish) Fatal errors ...
runfalk's user avatar
  • 193
1 vote
1 answer
194 views

Probabilistic (~50%) error on boot regarding "wrong fs type, bad option, bad superblock...missing codepage or helper program, or other error"

I've found a ton of posts on the internet regarding this error: wrong fs type, bad option, bad superblock on /dev/xxx,missing codepage or helper program, or other error Yet I have never found any case ...
Dennis Orlando's user avatar
1 vote
1 answer
766 views

How does the OS access files stored on the hard disk?

I know the first thing the OS accesses on the harddisk is the superblock. But then what?
Soumik Basu's user avatar
1 vote
1 answer
14k views

How to fix bad magic number - Superblock on Linux

I'm running a dual boot system with Windows 7 and Puppy Linux Ubuntu based "Bionic" installed on a separate partition of my main drive. Completely separate from that I have a 1TB Western Digital ...
Gary Platon's user avatar
1 vote
1 answer
251 views

Unix ext2 superblock - file system creation date

I am trying to find the creation date on an ext2 file system. I seem to get a current date using dumpe2fs. The problem is that the original ext2 superblock specification does not contain such ...
Panagiotis Stefanis's user avatar
1 vote
1 answer
609 views

All superblocks corrupt, mismatched start sector on extended and logical partitions

While running Linux Mint 19 Cinnamon normally, the drive went into lockdown mode preventing disk writes indicating possible corruption. Upon shutdown and reboot I was met with ACPI errors. Following ...
zolt56's user avatar
  • 13
1 vote
1 answer
1k views

Manually backup superblock - how to & does it make sense?

Background The first block of an ext4 filesystem is called the superblock - it contains essential metadata. There are backup copies of the superblock scattered throughout the filesystem; they can be ...
nagamani's user avatar
  • 181
1 vote
1 answer
3k views

An existing mdadm RAID5 is not mounting, Either a problem drive or Superblock

I have 4 x 3TB NAS setup as RAID5 which has been working great for almost a year. After a recent abrupt shutdown (had to hit the power button) the RAID will no longer mount on boot up. I've run: ...
Adamation's user avatar
1 vote
1 answer
1k views

e2fsck giving some error

I am playing with LVM and while doing lvreduce. I now get this error: [root@localhost raja]# e2fsck -f /dev/vg1/lvol2 e2fsck 1.41.12 (17-May-2010) e2fsck: Superblock invalid, trying backup blocks... ...
Raja G's user avatar
  • 5,927
1 vote
2 answers
555 views

Are Superblock and Master File Tables the same thing?

What is the difference between a superblock and a Master File Table (MFT)? Both seem to be tables that keep track of files within a filesystem, but are there other differences? The only difference I ...
Tommaso Bendinelli's user avatar
1 vote
1 answer
1k views

Bad magic number in super-block: dm-crypt device

I have a device that is encrypted using dm-crypt. This is a mini SD card that I use on my laptop. I've had some issues with my laptop freezing recently, and in the journal these messages come up: ...
user avatar
1 vote
1 answer
1k views

bad magic number in superblock

I need to restore a broken partition superblock, so I get my list of backuped superblocks with : sudo mke2fs -n /dev/sdd1 And I would like to know if when choosing the one to restore, if this is ...
John Doe's user avatar
  • 1,011
1 vote
1 answer
2k views

Recovering from bad superblock on external drive

read a few similar questions/posts and tried the solutions, still stuck. My scenario is simple, external ext4 drive was powered off (via cat) while operating, and failed to mount on boot. As I dug ...
lars's user avatar
  • 63
1 vote
0 answers
919 views

How did my ext3 superblocks get so messed up? And how to fix them?

I've recently found an old external hard disk and I have no idea what's on it. There was only one partition, encrypted with dm-crypt. Luckily I still remembered some of the passphrases that I used ...
meeque's user avatar
  • 21